1. Technical Field
The present disclosure relates generally to hinge assemblies and, more particularly, to a hinge assembly for electronic device.
2. Description of the Related Art
An electronic device such as a mobile phone, a notebook computer, or a personal digital assistant (PDA) generally has a main body and a cover with a display and a camera lens pivotally mounted on the main body via a typical hinge assembly.
Referring to FIG. 4, the typical hinge assembly 10 includes a shaft 11, a rotatable stand 12, a fixed stand 13, a restricting member 14, a cam 15, a cam follower 16, a plurality of spring washers 17, and a nut 18. A cross-section of the shaft 11 perpendicular to an axis of the shaft 11 is double-D shaped. A flange 111 is formed on a proximal end of the shaft 11, and a threaded portion 112 is formed on a distal end of the shaft 11. The rotatable stand 12 defines a pivot hole 121 for receiving the distal end of the shaft 11. A limiting protrusion 122 is formed on the rotatable stand 12 adjacent to the pivot hole 121. The rotatable stand 12 also defines a fixing hole 123 adjacent to the pivot hole 121. The fixed stand 13 defines a through hole 131 for receiving the proximal end of the shaft 11. The restricting member 14 defines an assembling hole 141 in a center portion of the restricting member 14. The restricting member 14 defines a limiting groove 142 in an edge portion of the restricting member 14. The cam 15 defines a cam hole 151 for receiving the distal end of the shaft 11. A fixing pole 152 extends from the cam 15. Two protrusions (not shown) opposite to each other are formed on a side surface of the cam 15 adjacent to the cam hole 151. A center of the cam follower 16 defines a pivot hole 161 for receiving the distal end of the shaft 11. The cam follower 16 defines two cutouts 162 on the cam follower 16 surrounding the pivot hole 161. The cutouts 162 are configured for engaging with the protrusions of the cam 15. The through hole 131 of the fixed stand 13, the cam hole 151 of the cam 15, and the pivot hole 161 of the cam follower 16 are non-circular holes corresponding to the shape of the cross-section of the shaft 11. The restricting member 14, the cam 15, and the cam follower 16 are generally made of a metal via powder metallurgy technique, to get a high rigidity and durability. The rotatable stand 12 and the fixed stand 13 are generally made of an alloy with a low rigidity, to reduce the manufacturing cost of the hinge assembly 10.
In assembling the hinge assembly 10, the threaded portion 112 of the shaft 11 extends through the assembling hole 141 of the restricting member 14, the pivot hole 121 of the rotatable stand 12, the cam hole 151 of the cam 15, the pivot hole 161 of the cam follower 16, the spring washers 17, and finally engages with the nut 18. The fixed stand 13 is fixed to the shaft 11 and touches the flange 111. The fixing pole 152 is inserted into the fixing hole 123 of the rotatable stand 12. The fixed stand 13, the restricting member 14, the cam follower 16 is non-rotatably connected to the shaft 11.
In use, the fixed stand 13 is rotated relative to the rotatable stand 12, and drives the shaft 11 to rotate, thus driving the restricting member 14 and the cam follower 16 to rotate. The limiting protrusion 122 of the rotatable stand 12 slides in the limiting groove 142 of the restricting member 14, in order to define a rotating angle range between the rotatable stand 12 and the fixed stand 13.
However, in assembling the hinge assembly 10, the nut 18 should be adjusted on the threaded portion 112 of the shaft 11 for a period of time, so that the spring washers 17 can produce an appropriate elastic force along the shaft 11. Therefore, an assembling efficiency of the hinge assembly 10 is low.
Therefore, a hinge assembly to solve the aforementioned problems is desired.